Pressure regulator



May l30, 1944. K. w` wEsTLUND PRESSURE REGULATOR Filed July 1, 1940 T-3. la

MQW@

HE EN ton) but i'or simplicity I shall use the term Patented Mey so, Aw44 UNITED STATES lMTENT fori-'ice y 4.rlaozz y e nessuna nsonm'roa :mi w. wenn animan ruk, onu.. usixnor to lnllallnflcarbnretor Co., Ltd., Huntington Park. Calif., a corporation of California Application July l, 1940, Serial No. 343,443

MCIalina.

My invention relates to pressure regulators of the multiple-stage type, the general object of the invention being to provide such a regulator with improved means for increasing its effective volumetric rangeof operation audits speed oi re' sponse to variations of outlet pressure. These general objectives, and others, and the general characteristics oi' my improvements will be understood from the iollowingwgeneral discussion and the succeeding detailed description of a speciilc illustrative embodiment of the invention.

Multiple-stage pressure regulators in which the ing the actuating pressure which is effective' on pressure controlled output of one regulator unit is fed into the inlet of a successive unit, are typified in two-stage regulators such as I use here I or descriptive purposes. Commonly such a regulator comprises a irst stage regulator unit and f a second stage regulator unit, each unit including apressure control valve and a movable pressureactuated valve-operating element which is usually a diaphragm. That element may be any pressure actuated means (such for instance as a pisdiaphragm to indicate any such element.

Theinitial high uid pressure is fed to the inlet side of the high pressure ilrst stage valve which, upon opening, feeds fluid into an intermediate pressure passage which leads to the inlet side of the low pressure second stage valve. Fluid at intermediate pressure is applied to thefirstA stage diaphragm to move it in a direction to close the high pressure ilrst stage valve, which it does when the intermediate pressure reaches the point determined by the reference pressure which is applied to that diaphragm tending to open the valve. At low or constant operating speeds the intermediate pressure is thus maintained substantially constant, if the effect of variations of the initial high pressure on the high pressure valve be disregarded or eliminated by using a balanced valve.

Any such regulator has certain inherent functional shortcomings, among which are (a) a lag in initial response and in response to variations of the delivery pressure due to variations of the demand on the delivery,-` and i(l2) a. lowering of `the delivery pressure as the volumetric Speed of operation increases. Various arrangements have been made to overcome these deilcienciesmore or less effectively and to give such av regulator a wide range of operating capacity.y One such arrangement is shown in the Ensign Patent 2,248,- 222 where the intermediate pressure is raised, as the low pressure falls andvelocitiesincrease, by picklngup a part of the velocity head from the the' first stage diaphragm to close the first stage valve; lowering that effective valve-closing pressure as the operating velocities increase and consequently raising the intermediate pressure which is delivered 'to the second stage regulator unit. Tins control operation, as will be explained, is of such a nature that the response to changing outlet pressures is much accelerated. These and Vother characteristics 'of my invention are explained in the followingv detailed description of an illustrative embodiment'oi' the invention, reference for that purpose being had to' the accompanying drawing inwhich Fig. 1 is a plan section, taken partially on lines I-I of Figs. 2 and 3, and partially on line I a-Ia of Fig. 3; n

Fig. 2 is a fragmentary section taken on line 2--2 of Fig. 1; and y Fig. 3 is a fragmentary section taken on line 3-3 of Fig. 1.

In the drawing a suitable housing is shown at I0 provided with a cover Il on one face, and provided at the other face with a member I2 which, together with housing wall I3, forms a water jacket surrounding-aheatingcoil I4. Although my invention is not limited to regulators in which the iluid is heated at intermediate pressure, my invention' has peculiar utilities as applied to a regulator structure in which the intermediate pressure passage is rather long or in which there is a pressure drop, and that is usually true in regulators which provide arrangements for heating the uid at intermediate pressure.

In the regulator design as here illustrated, the major part of the enclosure of casing I0 formsa low pressure chamber I5 which has a iinal low pressure outlet at the tting I6. One side of this vlow pressure chamber. is formed by the low pressure or second stage diaphragm Il which, in this particular illustration, is subjected onits outer surface toV atmospheric pressure as `a referencepressure to the for instance. goes to the intake of a gas engine. My invention is applicable and useful, regardless of the nature of the second stage reference pressure.

Within the interior of the main casing an `intermediate pressure diaphragm chamber I9 is formed by the wall ZII, the casing wall I3, and the flrststage diaphragm 2| which is secured to wall 20 under a cover 22. In this particular illustration, the first stage diaphragm chamber I9 is below diaphragm 2|, and cover 22 forms a lirst stage reference pressure chamber 23 above diaphragm 2l. In the illustrative design which is here shown, the first stage diaphragm is acted upon by a reference pressure which includes as one factor the low pressure from low pressure chamber I 5,v admitted to chamber 23 through aperture 25 in cover 22; As will be explained, the first stage valve 'opens whenever the diaphragm actuating pressure in chamber I9 is less than the total reference pressure on the diaphragm. Diaphragm spring 24 (as also valve spring 33, referred to later) adds a certain fixed `amount of reference pressure to the reference pressure which is obtained from the low pressure chamber. Consequently the first stage valve will open whenever pressure in chamber I9 falls below a figure which depends upon the low pressure existing at the instant.

That arrangement is a desirable one in that it tends to keep the intermediate pressure normally at a certain xed value above the low pressure at which the regulator delivers, and in that adjustable change of the low pressure by changing the second stage reference pressure is automatically followed by a corresponding change in the normal intermediate pressure. However, such an arrangement in multi-stage regulators has the disadvantage that when the low pressure falls during operation of the regulator, the firststage diaphragm tends to close the first-stage valve and to lower the intermediate pressure rather than to raise it. It is one of the features inherent in my invention that its mode of operation overcomes that particular disadvantageous characteristic.

As shown in the drawing, the initial high pressure inlet is through the nipple shown at 30, the inner end of this nipple carrying the valve seat 3| upon which the first stage valve 32 seats against the opening pressure of valve spring 33. The first stage valve 3| is mounted on valve stem 32a which projects through a wall 29 into first stage diaphragm chamber I9. The end of valve stem 32a is connected with first stage diaphragm 2| preferably in the manner shown in Fig. 2. A lever member 29 is pivoted at 34 and has an arm 35 connected with a stud 36 mounted on'first stage diaphragm 2|. Member 29 carries a plunger 3l normally pressed forward by a spring 38 to a position which is limited by stop pin 39. The end of valve rod 32a seats in a depression in the outer end of plunger 31. Spring 38, prestressed by the setting of pin 39, is stronger than valve opening spring 33, so that in the -normal operation of the regulator spring 38 is not compressed. But if at any time an excessive valve closing pressure should occur in diaphragm chamber I9 (due for instance to leakage past valve 32) the compression of spring 38 will limit the closing pressure which can be placed on valve 32 and thus protect that valve from injury by excessive pressure. It also allows diaphragm 2| to move back against cover 22 for support against high pressure.

Wall 29 forms a part of the enclosure of diaphragm chamber I9 and also encloses a passage til which forms a part of the intermediate pressure passage leading from valve 3| to the second stage valve. As here illustrated, the passage communicates, via a passage 5I, with the inlet end of the heater coil I4 which is located in the water jacketing or heating chamber enclosed by member I 2. Any suitable means (not shown) of passing hot water or other heating agent through the chamber may be used. The outlet end of heating coil 42 connects with a fitting 43 which in turn connects with passage 14 leading to the valve seat |15 of the second stage or low pressure valve 86. In my invention, this valve becomes what I refer to as the main low pressure or second stage valve. The passages 40, 4I, coil I4, 'and passages I3 and M may be broadly considered as the intermediate pressure passage leading from the first stage or high pressure valve to the second stage or low pressure valve, As shown, and particularly when such a passage includes a heating coil, it is rather long. And in such a long passage, and particularly one in which the uids are being heated and expanded, the effective intermediate pressure available at the low stage valve drops off very rapidly as the volumetric speed of the regulator increases. My invention has peculiar adaptability, although not limitedly, to regulators which include such a long intermediate pressure passage.

In accordance with my invention, I primarily provide such a regulator as has here been typically described, or any multiple stage regulator, with a means for restrictedly feeding the intert mediate pressure into the first stage diaphragm chamber I9, and then provide means, actuated by virtue of the pressure in low pressure chamber I5 (or the outlet pressure of the regulator) to bleed off and lower the first stage actuating1 pressure in diaphragm chamber I9 as the low pressure or outlet pressure drops. These provisions illustratively, but not limitedly, take such forms as I will now describe and which also include other features and functions as I will point out.

As shown in the drawing a restricted orifice 50 leads through -wall 29 from passage 40 into diaphragm chamber I9. Looseness around valve stem 32a at 5| where it passes through wall 29 may also constitute a restricted connection between 40 and I9. Either or both of these restricted communications may be regarded as a restricted communication from the intake end of the intermediate pressure passage to diaphragm chamber I9.

A passage 52, preferably relatively large and @0 unrestricted, leads from diaphragm chamber I9 to a point preferably adjacent the intermediate pressure passage B4 (see Fig. 2). Passage 52 is controlled by an auxiliary or pilot valve 62 which will presently be described. Another restricted orifice 53 communicates between intermediate pressure passage 44 and the passage 52, as shown in Fig. 2; orifice 53 being located in such positional relation to passage M that, at certain phases of operation it will be subject' to the velocity caused depression existing in passage 44 when the velocity there is relatively high. This action will bereferred to later. The primary function of orifice 53 is to establish a restricted communication between the delivery end of the intermediate pressure passage and the passage 53 the restricted orifice 53 and passage 52.

assassin and diaphragm chamber I9. It is convenient that passages M and 52 be mutually adjacent, to

facilitate the assembly of valves 40 and 82 into sage which leads directly iron; first stage valve 32 to second stage valve 4B and the orifice 53. And consequently, pressure in the intermediate pressure passage is maintained higher than it normally would be. These described conditions are maintained, in spite of the iact that the iliary valve seat 5I which is closed by auxiliary valve t2. The main valve d8 is mounted on a valve lever G3 which is pivoted on seat unit il@ at a spring or pair of springs t5 tending to close the main valve against the intermediate pressure. auxiliary valve 62 is mounted on a valve lever tt pivoted on unit t@ at G1 and is closed by spring lit againstthe intermediate pressure. A stem ed is aiilxed to second-stage diaphragm il and moves with it. This stem has a relatively large portion 'lil which passes freely through the end of main valve lever t3 and, in the non-operating Yposition of the parts with all the valves closed,

just rests at its lower end upon the end of auxiliary valve lever llt. A small pin ll at the end oi larger part it may pass through lever t6 to form a guide. In the position which has been referred to and shown in Fig. 2, an enlargement or collar l2 at the upper end of part it of pin is located a short distance above main valve lever t3. The arrangement is such that as diaphragm il moves down to open the second stage valves, auxiliary valve lever t6 is ilrst pushed down to lift auxiliary valve t2 ofi" its seat, and then enlargement l2 contacts main valve lever it to open the main valve.

Assuming that the low pressure outlet at iii is closedy (or that the pressure in low pressure chamber i 5 is higher than that at which the regulator is set to deliver) the full intermediate pressure for which iirst stage diaphragm 2| is set will be standing in diaphragm chamber t9, also in the whole length of the intermediate pressure passage from nrst stage valve t2 to secand stage valve 46. and also in passage 5t between first stage diaphragm chamber i9 and auxiliary valve 62. Fluid will be standing in low pressure chamber l5 at substantially the low pressure at which the second stage diaphragm il is set to close the second stage valves. in this description that pressure is assumed to be approximately atmospheric, but it may be any suitable or desired pressure.

As soon as pressure in low pressure chamber it is lowered, as by starting an engine to which the outlet of the regulator is connected, low pressure diaphragm I1 moves ilrst to open pilot valve Si?. As soon as that valve is opened the immediate effect is to reduce the pressure in passage 52 and in rst stage diaphragm chamber i9. This immediate reduction of pressure in chamber I9 causes ilrst stage valve 32 to open to increase the pressure in the intermediate pressure passage leading from rst stage valve 32 to second stage valve 46A and to restricted orifice 53. Fluid at the increased intermediate pressure tends immediately to enter iirst stage diaphragm chamber I9 through the restricted orifice 50 and through But both these orifices being restricted, and valve 62 beingopen, the pressure in passage 52 and in diaphragm chamber I9 is maintained somewhat lower than it is in the intermediate pressure pasorice through auxiliary valve seat Si may be also relatively small. The valve seat oriiice passes duid under a pressure differential whichis measured by the diierence between the low delivery pressure .and the modied intermediate pressure existing in the nrst stage diaphragm chamber. Passage 52 being preferably relatively wide open and unrestricted, the reduction of pressure eftected by discharge through the auxiliary valve is immediately transmitted to the first-stage diaphragm chamber it. On the othernand, the rej'stricted orifices at 5l) and 53 are only passing uuid under a pressure diiierential which is measured by the amount by which the pressure in 5l and is is lowered below that in the intermediate pressure passage leading from valve 32 to valve at. Thus, a relatively small pilot valve will effectively and quickly lower the pressure to a substantial degree in that chamber. And that is true even if the part of passage 52 lying between valve seat el and orifice 53 is relatively restricted-any restriction at that point may be regarded simply as restriction in or at the valve seat. The use oi' a small pilot valve is particularly desirable as it requires only a light spring and will open on a very slight drop of the outlet pressure. Further discussion of the relative sizes of the passages and orices is given later.

For small volumetric requirements, as for feeding an idling engine, the regulator may supply the required volume of gas with only pilot valve tt open. in that type ci' operation as well as in initial opening the two restricted orifices and b3 may be regarded as performing essentially the same function; that of restrictedly feeding intermediate pressure into the iirst stage diaphragm chamber i9 and to the pilot valve. With the fluid moving slowly'through the main intermediate pressure passage t0, il, 43, IN, the pressures in that passage at the orifices 50 and 53 may be regarded as substantially equal.

Passage 52 and the pilot valve are therefore restrictedly fed by both orlces 50 and 53; the pressure in passage 52 and diaphragm chamber i9 being lowered to a point somewhat under the normal or standing intermediate pressure, and valve t2 being consequently opened to increase the intermediate pressure in the intermediate pressure passage until balance is attained. This build-up of the intermediate pressure, on initial opening of the pilot valve, not only accelerates the response of the regulator to initial opening and facilitates delivery at low volume, but also gives a preliminary build up of the intermediate pressure in anticipation of the opening of the main second stage valve. That anticipatory increase of the intermediate pressure acting on the lower face of the main valve makes that valve open more easily against the spring pressure,l

which only has to hold the valve closed against the normal or standing pressure.

When pressure in low pressure chamber I5 is further reduced by increased requirements on the regulator, low pressure diaphragm I1 moves further` to onen main valve 46. Fluid then begins moving through the main intermediate pressure passage at higher velocity and discharges into the low pressure chamber via main valve 46 in addition to discharge through the pilot valve.

At such higher velocities, the pressure at the discharge end of the intermediate pressure passage. near valve 46 and orifice 53, becomesless than it is at the head end of that passage at first stage valve 32 and at restricted orice 50. The pressure at the discharge end of the passage, at restricted orifice 53, may become low enough that fluid ow through orifice 53 will be relatively reversed, so that uid ows from. passage 52 via orifice 53 into the main intermediate pressure passage 44. Thus, in relatively wide open operation of the regulator, both the flow through pilot valve 6I (which isstill open or even opened more widely), and also the increased .velocity of gas ow in main passage 46 past orifice 53, may both have the effect of directly lowering the pressure in passage 52 and in zirst stage diaphragm chamber I9. and of consequently boosting the pressure in the main inrestricted orifices 50 and 53 connecting diaphragm chamber I9 with both the head end and the discharge end of the long intermediate pressure passage, surges in that long passage and resultant chattering operation of the regulator are avoided. This provision is thought to be of some importance in a regulator where the fuel is heated and vaporized in a heating passage located between the two restricted orifices.

The general function of the valve controlled passage 52 leading from rst stage diaphragm flamber I 9 to the low pressure chamber I5 is thus not only to obtain a quick initial build-up of intermediate pressure in the main intermediate passage when the regulator first opens, but also thereafter to maintain a higher pressure in the main intermediate pressure passage than would normally be maintained. As thev main valve opens wider -in response to greater demand the pilot valve lifts further off its seat and may thus open more widely to increase the resulting pressure drop in the first stageediaphragm chamber. and thus to further increase the build-up of the intermediate pressure. Thus the pilot valve may have not only the function of initially building up the pressure and maintaining the build-up, but also the function of further increasing the pressure build-up as the main valve opens wider. This not only results in quick build-up of pressure on initial opening but also results in faster response to varying demands and in a much greater operating range for any given sized regulator, due to the fact that the effective intermediate pressure, in the intermediate pressure passage, may be built up to pressure substantially above normal when the regulator is operating at high velocities. And, as remarked before, the peculiar placement of restricted orice 53 also has similar functions when the regulator is operating at high velocities.

There are several distinct phases of operation of the regulator. In the low demand phase when only the pilot valve 62 is open, the regulator operates just as if main valve 46 were nonexistent-that is, just as if the second stage valve means included only the one valve instead of two, and that one valve controlled the passage 52 which leads from and controls the pressure in first stage diaphragm chamber I9, that chamber and the passage 52 being restrictedly fed from the main intermediate pressure passage.

' hind the opening of that valve.

And what has just been said is the same as saying that, in theV low demandVV phase, Aboth the outlet 52 from the restrictedly fed diaphragm chamber I9, and the main intermediate pressure passage Ill-44, via restricted orifice 53, lead to one and the same valve 62.

In the high demand phase of operation, with both valves 46 and 62 open, the action of auxiliary valve 62,I controlling the discharge from diaphragm chamber I9 and thus controlling the boosting of the intermediate pressure, still continues (and may be supplemented by the described action of orice 53). But the action of auxiliary valve t2` at that time does not depend upon its having opened first. So, again in this phase 'of operation, the two valves may be considered as one.

But the preliminary opening of pilot valve 62- its opening ahead of the Iopening of main valve IIE--builds up the intermediate pressure to feed main valve 46 ahead of rather than lagging be- In this phase of the operation the sequentially, opening valve means, or a multiple valve, is important.

It may also be remarked that certain functions of my improved regulator do not require all of the apparatus elements which have been described. For instance, it will be remembered that in the initial opening phase and in the phase of low operation with only the auxiliary valve open, orice 52 performs the same function as orifice 50. In those phases of operation both orifices merelyl restrictively feed intermediate pressure to the first stage diaphragm chamber and to the auxiliary valve. Consequently one or the other orifice can be dispensed with. y And in the high demand phase of operation the same is true. For instance the auxiliary valve can be used exclusively to control the modified pressure in the diaphragm chamber, without being aided by the action of orifice 52. Thus, although the action of that orifice is desirable in the latter operational phase, it is not indispensible.

Considering only the action of the auxiliary valve for controlling the diaphragm chamber pressure, it is only necessary that there be some restricted admission of intermediate pressure to the diaphragm chamber and that the auxiliary valve control the bleeding off of that pressure. For that purpose it is not necessary, although preferable, that the bleeding off passage 52 be relatively unrestricted. The whole passage, including the valve, might be substantially as small as the pressure inlet passage, but with the valve wide open the pressure in the diaphragm chamber would be reduced to half the pressure in the intermediate passage (speaking of a final delivery at atmospheric pressure, and of pressures above atmosphere). If passage 52 is made relatively wide open the modification range of pressure in the diaphragm chamber, and therefore the range of pressure increase. in the intermediate pressure passage is increased. The wide open passage is consequently preferable for that reason; and is.also preferable in connection with the functions of orifice 53 in reducing the pressure in the diaphragm chamber when that oriflce is in the position shown. With that orifice communicating with passage 52 near the auxiliary valve it is desirable that passage 52 be open from the orice to the diaphragm chamber.

The main advantages of my improved regulator reside in its quick response and wide range of volumetric capacity, and in other features which I have pointed out. 'I'here are also other inherent or incidental advantages, among which I may mention that. for any given capacity, a smaller regulator and, particularly, smaller valves than usual may be used-which are desirable because of the smaller pressures necessary to close them and because of the lesser effects which are had on the regulator by variations in the initial high pressure. And another feature is that an engine, for instance, may be properly fed for both idling and normal operation through a single connection with the regulator.

claimv as my invention:

l. in a two-stage fluid pressure regulator having a high pressure inlet. a first stage regulator means. including a'valve and a valve operating diaphragm, for reducing the high inlet pressure to an intermediate pressure, an intermediate pressure passage, a diaphragm chamber located on that side of the diaphragm where pressure on it tends to close the valve, a low pressure chamber, and a second stage regulator actuated bv pressure in the low pressure chamber and including a valvular means which controllably admits uid from the intermediate pressure passage to the low pressure chamber; the combiation of means forming a restricted communication tion from the intermediate pressure passage to the nrst stage diaphragm chamber to restrictedly apply intermediate pressure thereto, and a stage regulator so that said valvular means admits :duid directly from the rst stage diaphragm chamber to the low pressure chamber.

2. In a two-stage iiuid pressure regulator having a high pressure inlet, a iirst stage regulator means, including a valve and a valve operating diaphragm, for reducing the high inlet pressure to an intermediate pressure, an intermediate pressure passage, a diaphragm chamber located on that side of the diaphragm where pressure `on it tends to close the valve, a low pressure chamber, and a second stage regulator actuated by pressure in the low pressure chamber and including a valvular means which controllably admits iluid from the intermediate pressure passage to the low pressure chamber; the combination of means forming a restricted communication from the intermedaite pressure passage to the ilrst stage diaphragm chamber to restrictedly apply intermediate pressure thereto, and a passage leading from the ilrst stage diaphragm chamber to the valvular means of the second stage regulator so that said valvular means admits iluid directly from the ilrst stage diaphragm chamber to the 10W pressure chamber, the valvular means of the second stage regulator comprising two separate valves which respectively control the intermediate pressure `passage and the relatively unrestricted passage leading from the diaphragm chamber.

3. In a two-stage fluid pressure regulator having a high pressure inlet, aiirst stage regulator Y means, including a valve and a valve operating diaphragm, for reducing the high inlet pressure to an intermediate pressure, an intermediate pressure passage, a diaphragm chamber located on that side of the diaphragm where pressure on it tends to close the valve, a low pressure chamber, and a second stage regulator actuated by pressure in the low pressure chamber and including a valvular means which controllably admits fluid from the intermediate pressure paspassage leading from the rst stage diaphragm 4 chamber to the valvular means of the second stage regulator so 'that said valvular means admits iluid directly from the rst stage diaphragm chamber to the low pressure chamber, the valvular means of the second stage regulator being adapted to open the relatively unrestricted pas sage to the low pressure chamber before opening the intermediate pressure passage to that chamber.

i. In a two-stage fluid pressure regulator having a high pressure inlet, a iirst stage regulator means, including a valve and a valve operating diaphragm, for reducing the high inlet pressure to an intermediate pressure, an intermediate pressure passage, a diaphragm chamber located on that side of the diaphragm where pressure 4on it tends to close the valve, a low pressure chamber, and a second stage regulator including a diaphragm actuated by pressure in the low pressure chamber and valvular means which controllably admits iiuid from the intermediate pressure passage of the low pressure chamber; the come bination of means forming a restricted communication from the intermediate pressure passage t0 the iirst stage diaphragm chamber to restrictedlv Iapply intermediate pressure thereto, and a passage leading from the first stage diaphragm chamber to the valvular means of the second stage regulator so that said valvular means admits iiuid directly from the ilrst stage diaphragm chamber to the low pressure chamber, the valvular means of the second stage regulator compris ing two separate valves which respectively control the intermediate pressure passage and the relatively unrestricted passage leading from the iirst stage diaphragm chamber, and actuating connectionbetween the two said valves and the second stage regulator diaphragm such that the second mentioned one of saidvalves is opened before the other said valve as the pressure in the low pressure chamber decreases.

5. In a two-stage fluid pressure regulator having ahigh pressure inlet, a first stage regulator meansincluding a valve and a valve operating diaphragm, for reducing the high inlet pressure to an intermediate pressure, an intermediate pressure passage, a diaphragm chamber located on that side of the diaphragm where pressure on it tends to close the valve, a low pressure cham` ber, and a second stage regulator actuated by pressure in the low pressure chamber and including a valvular means which controllably admits uuid from the intermediate pressure Dassage to the low pressure chamber, the first stage regulator means having means for applying pressure from the low pressure chamber to said iirst stage diaphragm asa reference pressure on that side where pressure on it tends to open the first stage valve; the combination oi means forming a restricted communication from the intermediate pressure passage to the rst stage diaphragm chamber lto restrictedly apply intermediate pressure thereto. and a passage leading from the iirst stage diaphragm chamber to the valvular means of the second stage regulator so that said valvular means admits iluid directly from the first stage diaphragm `chamber to the low pressure chamber.

6. In a two-stage duid pressure regulator hav- Ving a high pressure inlet, a first stage regulator means, including a valve and a valve operating diaphragm, for reducing the high inlet pressure to an intermediate pressure, an intermediate pressure passage, a diaphragm chamber located on that side. of the diaphragm where pressure on it tends to close the valve, a low pressure chamber,

and a second stage regulator actuated by pres- 1' sure in the low pressure chamber and including a valvular means which controllably admits iiuid from the intermediate pressure passage to the low pressure chamber, the first stage regulator means having means for applying pressure from the low pressure chamber to said first stage diaphragm as a reference pressure on that side where pressure on it tends to open the first stage valve; the combination of means forming a restricted communication from the intermediate pressure passage to the first stage diaphragm chamber to restrictedly apply intermediate pressure thereto, and a passage leading from the first stage diaphragm.

to an intermediate pressure, an intermediate pressure passage, a diaphragm chamber located on that side of the diaphragm where pressure on it tends to close the valve, a low pressure chamber, and a second stage regulator actuated by pressure in the low pressure chamber and including a valvular means which controllably admits fluid from the intermediate pressure passage to the low pressure chamber, the first stage regulator means having means for applying pressure from the low pressure chamber to said first stage diaphragm as a reference pressure on that side where pressure on it tends to open the first stage valve, the cornbination of means forming a restricted communication from the intermediate pressure passage to the first stage diaphragm chamber to restrictedly apply intermediate pressure thereto, and a passage leading from the first stage diaphragm chamber to the valvular means of the second stage regulator so that said valvular means admits fluid directly from the first stage diaphragm chamber to the low pressure chamber, the valvular means of the second -stage regulator being adapted to open the relatively unrestricted passage to the low pressure chamber before opening the intermediate pressure passage to that l chamber.

8. In a two-stage fluid pressure regulator having a high pressure inlet, a first stage regulator means, including a valve and a valve operating diaphragm, for reducing the high inlet pressure to an intermediate pressure, an intermediate pressure passage, a diaphragm chamber located on that side of the diaphragm where pressure on it tends to close the valve, a low pressure chamber, and a second stage regulator including a diaphragm actuated by pressure in the low pressure chamber and valvular means which controllably admits fluid from the intermediate 'pressure passage to the low pressure chamber,

the first stage regulator means having means for applying pressure from the low pressure chamber to said first stage diaphragm as a ,reference pressure on that side Where pressure on it tends to open the first stage valve; vthe com bination of means forming a restricted `communication from the intermediate pressure passage to the first stage diaphragm chamber to restrictedly apply intermediate pressure thereto, and a passage leading from the first stage diaphragm chamber to the valvular means of the second stage regulator so that said valvular means admits iiuid directly from the first stage diaphragm chamber to the low pressure chamber, the valvular means of the second stage regulator comprising two separate valves which respectively control the intermediate pressure passage and the relatively unrestricted passage leading from the first stage diaphragm chamber, and actuating connection between the two said valves and the second stage regulator diaphragm such that the second mentioned one of said valves is opened before the other said valve as the pressure in the low pressure chamber decreases.

9. Fluid pressure regulator as specified in claim 1, and in winch the means forming a restricted communicationbetween the intermediate pressure passage and the first stage diaphragm chamber includes a restricted orifice which communicates with the intermediate pressure passage at a point in that passage adjacent the second stage regulator valve, so that the pressure at said orice is modied by the pressure drop which is due to the velocity of fluid ow through the intermediate pressure passage.

10. Fluid pressure regulator as specified in claim 1, and in which the means forming a restricted communication between the intermediate pressure passage and the first stage diaphragm chamber includes two restricted orifices, one communicating .with the intermediate pressure passage at a point adjacent the first stage regulator valve and the other communicating with that passage at a point adjacent the second stage regulator valve.

11. Fluid pressure regulator as specified in claim 3, and in which the means forming a restricted communication between the intermediate pressure passage and the first stage diaphragm chamber includes a restricted orifice which communicates with the intermediate pressure passage at a point in that passage adjacent the second stage regulator valve, so that the pressure at said orifice is modified by the pressure drop which is due to the velocity of fluid flow through the intermediate pressure passage.

12. Fluid pressure regulator as specified in claim 3, and in which the means forming a restricted communication between the intermediate pressure passage and the first stage diaphragm chamber includes two restricted orifices, one communicating with the intermediate pressure passage at a point adjacent the rst stage regulator valve and the other communicating with that passage at a point adjacent the second stage regulator valve.

13. Fluid pressure regulator as specified in claim l, and in which the means forming a restricted communication between the intermediate pressure passage and the first stage diaphragm chamber includes a restricted orifice which communicates with the intermediate pressure passage in such orientation as to pick up the pressure drop which is due to flow velocity through the intermediate pressure passage, whereby the pressure which is restrictedly applied to said diaphragm chamber is modified by the velocity of flow through the intermediate pressure passage.

14. Fluid pressure regulator as specified in claim 3, and in which the means forming a restricted communication between the intermediate pressure passage and the rst stage diaphragm chamber includes a restricted orifice which communicates with the intermediate Dressure passage in such orientation as to pick up the' pressure drop which is due toow velocity through the intermediatel pressure passage. whereby the pressure which is restrictedly applied to said diaphragm chamber is modified by the velocity of flow through the intermediate pressure passage.

KARL W. WESTLUND. 

